An Overview of Discoid Eczema

Discoid eczema causes a raised, disc-shaped rash with a well-defined border. The patches are itchy, flaky, and may also weep and crust over. It most often develops on the lower legs, but can also appear on the arms, trunk, hands, or feet.

Discoid eczema is a chronic condition. The patches can last for months, or years in some cases, and are likely to reoccur. Discoid eczema is also called nummular eczema, nummular dermatitis, and discoid dermatitis.

Discoid Eczema Symptoms

Discoid eczema causes very distinct circular, raised patches of irritated skin. The patches have well-defined borders, and can range in size from a quarter-inch to up to 4 inches in diameter. Some people develop just one or a handful of patches; others may get dozens.

The rash caused by discoid eczema can be extremely itchy and may also burn. The skin becomes inflamed, scaly, or crusty, and the patches may crack and ooze.

The rash may heal completely between breakouts, but it doesn't always. It's quite common to have a breakout that lasts for many months.

Causes

No one knows exactly what causes discoid eczema to develop. What is certain is discoid eczema is more common in people who have a family history of atopic dermatitis (AKA common eczema), allergies, and asthma, or have one or more of these disorders themselves.

People with sensitive skin that is easily irritated by cosmetic products, rough clothing, and the like, are also more prone to developing discoid eczema.

Certain environmental factors things may trigger a breakout, including:

• Dry skin
• Stress
• Use of cosmetic products that cause irritation
• Certain medications, especially isotretinoin and interferon

Discoid eczema often first appears after an injury, even a relatively small one like a burn, scrape, or an insect bite. The rash can erupt anywhere on the body, but typically you'll find it on the lower legs, the arms, and the trunk. It doesn't often occur on the face.

Men are slightly more likely than women to develop discoid eczema. In men, discoid eczema most often makes its first appearance after age 50. Women, on the other hand, are more likely to see it develop in late adolescence and early adulthood. That said, it can happen across all ages, though it is fairly uncommon in children.

Diagnosis

There is no specific test for discoid eczema. Instead, it's diagnosed by visual exam and ruling out other possible causes for your rash.

In some cases, a healthcare provider can diagnose discoid eczema by simply looking at the rash and taking your medical history. Often though, your physician will want to do a skin scraping or skin biopsy to rule out other possible skin problems.

During a skin biopsy, a small bit of skin is removed so it can be studied under a microscope. The dermatopathologist (a pathologist specializing in dermatology) will look for fungi or bacteria that may be causing your rash. Your healthcare provider may also decide to do patch testing to test for allergies.

Discoid eczema can sometimes be mistaken for:

• Ringworm
• Psoriasis
• Lichen aureus
• Contact dermatitis

It's important that you get the correct diagnosis because, although they have similar symptoms, each of these skin problems is treated differently.

Treatment

Because discoid eczema can be difficult to get under control once it appears, most likely you'll need a prescription medication. To see the best results, it's imperative that you follow your healthcare provider's instructions exactly for whichever treatment is prescribed.

Medications

Medication options for discoid eczema include topical steroids, antibiotics, topical calcineurin inhibitors, antihistamines, and moisturizers.

Topical steroids are the most common treatment for discoid eczema. Topical steroids help reduce inflammation and irritation. You'll apply these creams once daily or up to several times daily, depending on the type of steroid and strength prescribed.

Topical steroids can cause thinning of the skin, hyperpigmentation (dark spots), and hypopigmentation (light spots), especially with long-term use. It's important to use topical steroids exactly as directed. Daily use is not advised.

Topical calcineurin inhibitors (TCIs) are a group of medications that include Elidel (pimecrolimus) and Protopic (tacrolimus). These medications are approved for use in atopic dermatitis, but are also sometimes prescribed for discoid eczema.

TCIs work by inhibiting the immune response that is triggering the rash. TCIs are not steroids, and they will not cause skin thinning and other scarring associated with repeated topical steroid use.

Oral antibiotics may be prescribed if your rash is infected, or if your discoid eczema is very severe.

Antihistamines are not typically effective in treating severe itch seen in different forms of eczema including discoid eczema. If, however, itchiness is interfering with sleep, sedating antihistamines can be useful.

Moisturizers should be used frequently. This is key to treating and preventing a recurrence. Apply an emollient cream immediately after bathing or showering, while the skin is still slightly damp.

Avoid Triggers

Whenever possible, try to avoid environmental factors that can trigger a flare-up of discoid eczema (provided you know what they are; in many cases you may not.) There are certain things that are more likely to trigger an outbreak. They include:

• Highly-fragranced personal care products⁠: Avoid perfumed soap, lotions, perfumes, and the like.
• Fragranced laundry products: These include detergents, fabric softeners, and dryer sheets.
• Rough or scratchy clothing: You may wish to avoid wool, nubby knit garments, etc.
• Dry indoor air⁠: Try running a humidifier and avoid running the heater whenever possible.
• Skin injury: Protect your skin from injury, even small wounds. For example, stay indoors when bugs are likely to be active and biting; wear gloves whenever working with your hands (if discoid eczema tends to develop on your hands).

Coping

Discoid eczema can be incredibly distressing to those who have it. You may feel like people are staring at your rash, or judging you for the condition of your skin.

Although it's common for people dealing with discoid eczema (and other visible skin conditions like psoriasis and acne) to feel embarrassed about their skin, do remember that discoid eczema is much more obvious to you than it is to anyone else.

Part of what makes discoid eczema so stressful is the feeling of being out-of-control of your own skin. You don't know when a breakout will occur and when it will go away.

Stress-relieving activities, like meditation, yoga, or even just a hobby that you enjoy, can help calm these feelings of frustration. What's more, some studies have shown that stress-relieving activities can also help reduce itching.

Dealing With Itching

The itching of discoid eczema can be unbearable at times. Some people find the itching is worst just as the rash develops, while others say the itch continues until the rash heals. Either way, there are steps you can take to reduce the itch:

• Place cool washcloths or ice packs over the rash to numb the area (wrap ice packs in a cloth first, don't apply directly to the skin).
• Apply a thick moisturizing cream, ideally one that contains ceramides. Remember, though, to stay away from products that contain fragrance or dyes as these can further irritate the skin. Read the ingredients label or ask your healthcare provider for a recommendation if you need help choosing a product.
• Use a wet wrap. Apply a damp cloth directly to the skin, and cover this with a dry covering. This can be left on overnight if itching is worse at night. (Do check with your healthcare provider before trying wet wrap therapy.)
• Keep your rash covered with soft pajamas or a wrap if you tend to scratch during sleep.

A Word From Verywell

Dealing with a chronic skin condition is never easy. When you're having a breakout, the pain and itching (and possible embarrassment) can impact your life.

The good news is, with careful and consistent treatment, discoid eczema can be effectively managed. Over-the-counter products are rarely helpful for this type of eczema, though. Instead, make an appointment with your healthcare provider so that you may get the correct diagnosis and treatment.